Language and the brain

Question 1

What size lateralisation do most humans have for language abilities

Answer 1

Left side

Question 2

What is Broca’s area associated with?

Wernicke’s?

Answer 2

Speech production
Speech comprehension

Both parts in L hemisphere

Question 3

How does a person’s handedness relate to their specialised language hemisphere?

Answer 3

Opposite to each other,

BUT majority of left handers also have left hemispheric specialisation of language abilities

Question 4

List 4 methods of determining language lateralisation

Answer 4

fMRI
ERP
Wada- sodium amytal- test
Transcranial magnetic stimulation

Question 5

Describe the Wada/sodium amytal test

Answer 5

Used by NPs prior surgery for temporal lobe epilepsy
Injection of sodium amytal into one hemisphere
Produce transient ipsilateral hemiparesis- temporary one sided weakness
If speech dominant hemiphere is injected, clear but transient speech impairment

Question 6

What do neuroimaging studies show?

Answer 6

PET and fMRI show dominance of L hemi in speech production and comprehension

Non speech verbal skills- humour, singing, metaphor, comprehension– R hemi activation

Different subregions of language areas are involved in different types of processing- noun word generation (red), concrete vs abstract (green)

Question 7

What do ERPs show

Answer 7

Non invasive, electrodes on scalp
Good time resolution- temporally accurate
1ms

Negative 400ms (N400)
Normal brain response to words and other meaningful stimuli, in visual or auditory modalities

400ms after word is said, it is received, N400 produced
Larger N400 when semantic mismatching
Reduced N400 amplitude in lang deficits eg Wernicke’s, Alzheimer’s, Parkinson’s, Schizophrenia

Question 8

Describe TMIs

Answer 8

coil placed a the back of the head and mag field enters the brain causing generation/ interruption of nerve impulses
Magnetic stimulation produces transient disruption of brain function

Question 9

Define aphasia

Answer 9

a partial or complete loss of language resulting from an organic cause
40% of strokes produce aphasia

Question 10

Describe Broca’s aphasia

Answer 10

Expressive aphasia, non fluent aphasia
Spontaneous speech confined to single words or syllables
Telegraphic speech
Function words emitted

Question 11

Define anomia

Answer 11

Difficulty finding words that label objects

Question 12

Define agrammatism

Answer 12

Problems processing grammatically complex sentences

Question 13

Describe Wernicke’s aphasia

Answer 13

Receptive/fluent aphasia
In left superior temporal gyrus
Fluent speech but doesnt make sense ‘word salad’ anosogonosia- unaware of deficit, semantic paraphrases(eg horse for cow)
Deep dyslexia (reading deficit)

Question 14

What is conduction aphasia

Answer 14

dont understand words that arent real

Damage to fasciculus arcuatus

Question 15

Describe the Wernicke-Geschwind Model

Answer 15

Wernicke’s area contains auditory codes for words and meanings
Broca’s contains articulatory codes- how to pronounce words
Word spoken–auditory code activated in Wernicke’s
Transmitted to Broca’s
activates articulatory code for word–>sends to motor cortex–> command to speak word

Question 16

Describe language disorder in schizophrenics

Answer 16

formal thought disorder - loss of goals and tangentiality
(resembles wernickes)

Disorganisation of thoughts and speech- jargon aphasia
- loss of goal

Disturbance in associated thought process- digress- tangeniality

Question 17

List the two types of reading

Answer 17

whole word and phonetic reading

Question 18

Describe the two types of dyslexia

Answer 18

surface dyslexia - trouble with whole word reading but can spell out phonetically
deep dyslexia - cant spell phonetically. often semantic paraphrasing. non familiar words read poorly